1. Field of the Invention
The present invention relates to an image forming apparatus using an electrophotographic system.
2. Description of the Related Art
In general, an image heating apparatus used for an image forming apparatus utilizing an electrophotographic system has a heating rotating member and a pressing rotating member that forms a nip along with the heating rotating member, and heats a toner image formed on a recording material while conveying the recording material through the nip.
The image heating apparatus often adopts a configuration in which one of the heating and pressing rotating members is rotationally driven, while the other one of the rotating member is driven as a result of drive of the one of the heating and pressing rotating members. In the image heating apparatus, when a recording material having absorbed moisture is heated while being conveyed through the nip, steam is generated. As is known, when the steam causes condensation on a surface of the heating rotating member or the pressing rotating member, the rotation speed of the driven rotating member decreases or the rotation is stopped, causing a phenomenon in which the recording material slips, that is, what is called a condensation slip.
Thus, Japanese Patent Application Laid-open No. 2013-137514 discloses an apparatus that extends a warm-up time in accordance with the temperature of a pressing roller to heat the surface of the pressing roller to hinder condensation.
However, disadvantageously, the extended warm-up time increases a first print out time (FPOT), degrading usability.